Ammonia (NH3) emission and redeposition play a major role in terrestrial nitrogen (N) cycles and can also cause environmental problems, such as changes in biodiversity, soil acidity, and eutrophication. Previous f...Ammonia (NH3) emission and redeposition play a major role in terrestrial nitrogen (N) cycles and can also cause environmental problems, such as changes in biodiversity, soil acidity, and eutrophication. Previous field grazing experiments showed inconsistent (positive, neutral, and negative) NH3 volatilization from soils in response to varying grazing intensities. However, it remains unclear whether, or to what extent, NH3 emissions from soil are affected by increasing grazing intensities in Inner Mongolian grasslands. Using a 5-year grazing experiment, we investigated the relationship between NH3 volatilization from soil and grazing pressure (0.0, 3.0, 6.0, and 9.0 sheep/hm2) from June to September of 2009 and 2010 via the vented-chamber method. The results show that soil NH3 volatilization was not significantly different at different grazing intensities in 2009, although it was higher at the highest stocking rate during 2010. There was no significant linear relationship between soil NH3 volatilization rates and soil NH4^-N, but soil NH3 volatilization rates were significantly related to soil water content and air temperature. Grazing intensities had no significant influence on soil NH3 volatilization. Soil NH3 emissions from June to Sep- tember (grazing period), averaged over all grazing intensities, were 9.6±0.2 and 19.0±0.2 kg N/hm2 in 2009 and 2010, respectively. Moreover, linear equations describing monthly air temperature and precipitation showed a good fit to changes in soil NH3 emissions (r=0.506, P=0.014). Overall, grazing intensities had less influence than that of climatic factors on soil NH3 emissions. Our findings provide new insights into the effects of grazing on NH3 volatili- zation from soil in Inner Mongolian grasslands, and have important implications for understanding N cycles in grassland ecosystems and for estimating soil NH3 emissions on a regional scale.展开更多
This paper firstly analyzed the operation model,market positioning,market demand forecast as well as market competition and challenges,park site selection,and transportation conditions for construction of the Cold-Cha...This paper firstly analyzed the operation model,market positioning,market demand forecast as well as market competition and challenges,park site selection,and transportation conditions for construction of the Cold-Chain Logistics Park of Agricultural Products in Sanshui.Then,it presented the overall planning scheme for construction of the Cold-Chain Logistics Park of Agricultural Products from a progressive two-stage perspective of overall planning and stage-by-stage implementation.The first stage mainly performs the function as a transaction platform of agricultural products and meanwhile provides customers with agricultural products storage and inspection services.The second stage adds value-added services such as distribution processing,modified atmosphere storage,freezing and refrigeration,market price information distribution,E-commerce of agricultural products and personalized services.It is expected to provide references and suggestions for the construction of the Cold-Chain Logistics Park of Agricultural Products.展开更多
The BRAF gene is an important signaling molecule in human cells that is involved in the regulation of cell growth,differentiation,and survival.When the BRAF gene mutates,it can lead to abnormal activation of the signa...The BRAF gene is an important signaling molecule in human cells that is involved in the regulation of cell growth,differentiation,and survival.When the BRAF gene mutates,it can lead to abnormal activation of the signaling pathway,which promotes cell proliferation,inhibits cell apoptosis,and ultimately contributes to the occurrence and development of cancer.BRAF mutations are widely present in various cancers,including malignant melanoma,thyroid cancer,colorectal cancer,non-small cell lung cancer,and hairy cell leukemia,among others.BRAF is an important target for the treatment of various solid tumors,and targeted combination therapies,represented by BRAF inhibitors,have become one of the main treatment modalities for a variety of BRAF-mutation-positive solid tumors.展开更多
Aims Precipitation pulses and different land use practices(such as grazing)play important roles in regulating soil respiration and carbon balance of semiarid steppe ecosystems in Inner Mongolia.However,the interactive...Aims Precipitation pulses and different land use practices(such as grazing)play important roles in regulating soil respiration and carbon balance of semiarid steppe ecosystems in Inner Mongolia.However,the interactive effects of grazing and rain event magnitude on soil respiration of steppe ecosystems are still unknown.We conducted a manipulative experiment with simulated precipitation pulses in Inner Mongolia steppe to study the possible responses of soil respiration to different precipitation pulse sizes and to examine how grazing may affect the responses of soil respiration to precipitation pulses.Methods Six water treatments with different precipitation pulse sizes(0,5,10,25,50 and 100 mm)were conducted in the ungrazed and grazed sites,respectively.Variation patterns of soil respiration of each treatment were determined continuously after the water addition treatments.Important Findings Rapid and substantial increases in soil respiration occurred 1 day after the water treatments in both sites,and the magnitude and duration of the increase in soil respiration depended on pulse size.Significantly positive relationships between the soil respiration and soil moisture in both sites suggested that soil moisture was the most important factor responsible for soil respiration rate during rain pulse events.The ungrazed site maintained significantly higher soil moisture for a longer time,which was the reason that the soil respiration in the ungrazed site was maintained relatively higher rate and longer period than that in the grazed site after a rain event.The significant exponential relationship between soil temperature and soil respiration was found only in the plots with the high water addition treatments(50 and 100 mm).Lower capacity of soil water holding and lower temperature sensitivity of soil respiration in the grazed site indicated that degraded steppe due to grazing might release less CO_(2) to the atmosphere through soil respiration under future precipitation and temperature scenarios.展开更多
Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors ...Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.展开更多
Aims Bacteria and fungi are two primary groups of soil microbes,and their stability determines the persistence of microbial functions in response to a changing environment.Recent studies reported higher fungal than ba...Aims Bacteria and fungi are two primary groups of soil microbes,and their stability determines the persistence of microbial functions in response to a changing environment.Recent studies reported higher fungal than bacterial stability under precipitation alteration,the underlying mechanisms,however,remain elusive.Methods A 3-year precipitation manipulation experiment in a semi-arid grassland was used to compare the bacterial and fungal diversities,including alpha diversity,beta diversity and microbial community composition turnover,in response to precipitation manipulations.A framework is proposed to understand the stability properties of bacteria and fungi under precipitation alteration.We conceived a diagrammatic valley to illustrate microbial stability with the depth representing resistance and the width ecological resilience.Important Findings We found that±60%in precipitation significantly reduced the richness and increased the evenness of bacteria but had trivial impacts on fungi.Precipitation alteration yielded stronger impacts on the variation in alpha diversity of bacteria than fungi,suggesting that the bacterial community is more sensitive to water stress than the fungal community.Moreover,fungi had wider composition turnover than that of bacteria,indicating higher composition variation of fungi than bacteria.The population turnover of fungi,reflected by composition variation,coefficient variation of diversity index and composition turnover,was larger than that of bacteria at both temporal and spatial scales,indicating the population turnover promotes fungal stability.The higher stability of fungal community in tolerating water stress is analogous to a ball in a wide valley that swing substantially but remain close to its steady state;while the lower stability of bacteria community is analogous to a ball that swings slightly but stay far away from its steady state.Our finding that the fungal community had higher stability than bacterial community in a semi-arid grassland might be applicable to other biomes.展开更多
This paper studies the backward-forward linear-quadratic-Gaussian(LQG)games with major and minor agents(players).The state of major agent follows a linear backward stochastic differential equation(BSDE)and the states ...This paper studies the backward-forward linear-quadratic-Gaussian(LQG)games with major and minor agents(players).The state of major agent follows a linear backward stochastic differential equation(BSDE)and the states of minor agents are governed by linear forward stochastic differential equations(SDEs).The major agent is dominating as its state enters those of minor agents.On the other hand,all minor agents are individually negligible but their state-average affects the cost functional of major agent.The mean-field game in such backward-major and forward-minor setup is formulated to analyze the decentralized strategies.We first derive the consistency condition via an auxiliary mean-field SDEs and a 3×2 mixed backward-forward stochastic differential equation(BFSDE)system.Next,we discuss the wellposedness of such BFSDE system by virtue of the monotonicity method.Consequently,we obtain the decentralized strategies for major and minor agents which are proved to satisfy the-Nash equilibrium property.展开更多
Aims Water and nitrogen(N)are two key resources in dryland ecosystems,but they may have complex interactive effects on the community structure and ecosystem functions.How future precipitation(rainfall vs snowfall)chan...Aims Water and nitrogen(N)are two key resources in dryland ecosystems,but they may have complex interactive effects on the community structure and ecosystem functions.How future precipitation(rainfall vs snowfall)change will impact aboveground net primary production(ANPP)is far from clear,especially when combined with increasing N availability.Methods In this study,we investigated changes in community productivity,abundance and aboveground biomass of two dominant plant functional groups(PFGs),i.e.perennial rhizome grasses(PR)and perennial bunchgrasses(PB)under the impacts of increased precipitation(rainfall vs snowfall)combined with N addition in a semiarid temperate steppe.Important Findings Summer rainfall augmentation marginally increased community ANPP,whereas it significantly increased the abundance and aboveground biomass of PR,but not those of PB.Summer rainfall addition increased the fraction of PR biomass(fPR)while decreased that of PB(fPB).Spring snow addition had no effect on aboveground biomass of either compositional PFG although it marginally increased community ANPP.Nitrogen addition significantly increased community ANPP with greater increase in PR under summer rainfall addition,indicating strong interactive effects on community ANPP largely by enhancing PR biomass.We also found a nonlinear increase in the positive effect of nitrogen addition on productivity with the increased precipitation amount.These findings indicate an amplified impact of precipitation increase on grassland productivity under the accelerated atmospheric N deposition in the future.展开更多
基金Funding for this work came from the National Natural Science Foundation of China (30830026)the National Basic Research Program of China (2009CB825103)the Innovative Research Group Project of the National Natural Science Foundation of China (30821062)
文摘Ammonia (NH3) emission and redeposition play a major role in terrestrial nitrogen (N) cycles and can also cause environmental problems, such as changes in biodiversity, soil acidity, and eutrophication. Previous field grazing experiments showed inconsistent (positive, neutral, and negative) NH3 volatilization from soils in response to varying grazing intensities. However, it remains unclear whether, or to what extent, NH3 emissions from soil are affected by increasing grazing intensities in Inner Mongolian grasslands. Using a 5-year grazing experiment, we investigated the relationship between NH3 volatilization from soil and grazing pressure (0.0, 3.0, 6.0, and 9.0 sheep/hm2) from June to September of 2009 and 2010 via the vented-chamber method. The results show that soil NH3 volatilization was not significantly different at different grazing intensities in 2009, although it was higher at the highest stocking rate during 2010. There was no significant linear relationship between soil NH3 volatilization rates and soil NH4^-N, but soil NH3 volatilization rates were significantly related to soil water content and air temperature. Grazing intensities had no significant influence on soil NH3 volatilization. Soil NH3 emissions from June to Sep- tember (grazing period), averaged over all grazing intensities, were 9.6±0.2 and 19.0±0.2 kg N/hm2 in 2009 and 2010, respectively. Moreover, linear equations describing monthly air temperature and precipitation showed a good fit to changes in soil NH3 emissions (r=0.506, P=0.014). Overall, grazing intensities had less influence than that of climatic factors on soil NH3 emissions. Our findings provide new insights into the effects of grazing on NH3 volatili- zation from soil in Inner Mongolian grasslands, and have important implications for understanding N cycles in grassland ecosystems and for estimating soil NH3 emissions on a regional scale.
文摘This paper firstly analyzed the operation model,market positioning,market demand forecast as well as market competition and challenges,park site selection,and transportation conditions for construction of the Cold-Chain Logistics Park of Agricultural Products in Sanshui.Then,it presented the overall planning scheme for construction of the Cold-Chain Logistics Park of Agricultural Products from a progressive two-stage perspective of overall planning and stage-by-stage implementation.The first stage mainly performs the function as a transaction platform of agricultural products and meanwhile provides customers with agricultural products storage and inspection services.The second stage adds value-added services such as distribution processing,modified atmosphere storage,freezing and refrigeration,market price information distribution,E-commerce of agricultural products and personalized services.It is expected to provide references and suggestions for the construction of the Cold-Chain Logistics Park of Agricultural Products.
基金supported by the Natural Science Foundation of China(grant number 82002456)China Postdoctoral Science Foundation(grant number 2022M723207)+10 种基金the Medical Scientific Research Foundation of Zhejiang Province,China(grant number 2023KY666)Zhejiang Traditional Chinese Medicine Science Fund Project(grant number 2024ZL372)Qiantang Cross Fund Project(grant number 2023-16)National Natural Science Foundation of China of Zhejiang Cancer Hospital Cultivation Project(grant number PY2023006)the Medical Scientific Research Foundation of Zhejiang Province,China(grant number 2024KY812)the Natural Science Foundation of Zhejiang Province(grant number LQ24H160036)Beijing Health Technologies Promotion Program[grant number BHTPP2022041]Peking University Clinical Scientist Training Program and the Fundamental Research Funds for the Central Universities[grant number BMU2024PYJH010]Science Foundation of Peking University Cancer Hospital[grant number PY202333]the Beijing Natural Science Foundation[grant number 7232248]Beijing Hospitals Authority Youth Programme[grant number QML20231902].
文摘The BRAF gene is an important signaling molecule in human cells that is involved in the regulation of cell growth,differentiation,and survival.When the BRAF gene mutates,it can lead to abnormal activation of the signaling pathway,which promotes cell proliferation,inhibits cell apoptosis,and ultimately contributes to the occurrence and development of cancer.BRAF mutations are widely present in various cancers,including malignant melanoma,thyroid cancer,colorectal cancer,non-small cell lung cancer,and hairy cell leukemia,among others.BRAF is an important target for the treatment of various solid tumors,and targeted combination therapies,represented by BRAF inhibitors,have become one of the main treatment modalities for a variety of BRAF-mutation-positive solid tumors.
基金The National Natural Science Foundation of China(90511001 and 30521002)an Action Plan for the Development of Western China of Chinese Academy of Science(KZCX2-XB2-01-04)a Knowledge Innovation Project of Chinese Academy of Sciences(KSCX2-SW-127).
文摘Aims Precipitation pulses and different land use practices(such as grazing)play important roles in regulating soil respiration and carbon balance of semiarid steppe ecosystems in Inner Mongolia.However,the interactive effects of grazing and rain event magnitude on soil respiration of steppe ecosystems are still unknown.We conducted a manipulative experiment with simulated precipitation pulses in Inner Mongolia steppe to study the possible responses of soil respiration to different precipitation pulse sizes and to examine how grazing may affect the responses of soil respiration to precipitation pulses.Methods Six water treatments with different precipitation pulse sizes(0,5,10,25,50 and 100 mm)were conducted in the ungrazed and grazed sites,respectively.Variation patterns of soil respiration of each treatment were determined continuously after the water addition treatments.Important Findings Rapid and substantial increases in soil respiration occurred 1 day after the water treatments in both sites,and the magnitude and duration of the increase in soil respiration depended on pulse size.Significantly positive relationships between the soil respiration and soil moisture in both sites suggested that soil moisture was the most important factor responsible for soil respiration rate during rain pulse events.The ungrazed site maintained significantly higher soil moisture for a longer time,which was the reason that the soil respiration in the ungrazed site was maintained relatively higher rate and longer period than that in the grazed site after a rain event.The significant exponential relationship between soil temperature and soil respiration was found only in the plots with the high water addition treatments(50 and 100 mm).Lower capacity of soil water holding and lower temperature sensitivity of soil respiration in the grazed site indicated that degraded steppe due to grazing might release less CO_(2) to the atmosphere through soil respiration under future precipitation and temperature scenarios.
基金supported by the National Natural Science Foundation of China(11464017,11864015)the Scientific Research Foundation for Universities from the Education Bureau of Jiangxi Province(GJJ170490)+1 种基金Foundation of Natural Science Funds for Distinguished Young Scholar of Jiangxi Province(20171BCB23064)the Science and Technology Major Project of Jiangxi Province(20165ABC28010).
文摘Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.
基金supported by the Chinese National Key Development Program for Basic Research(grant no.2017YFA0604802 and 2016YFC0500703)National Natural Science Foundation of China(grant no.31770526 and 41573063)+1 种基金Strategic Priority Research Program on Soil and Microbes of the Chinese Academy of Sciences(grant no.XDB15010401)Key Laboratory of Vegetation Ecology,Ministry of Education.X.X.acknowledges the financial support from the San Diego State University and the CSU Program for Education&Research in Biotechnology.
文摘Aims Bacteria and fungi are two primary groups of soil microbes,and their stability determines the persistence of microbial functions in response to a changing environment.Recent studies reported higher fungal than bacterial stability under precipitation alteration,the underlying mechanisms,however,remain elusive.Methods A 3-year precipitation manipulation experiment in a semi-arid grassland was used to compare the bacterial and fungal diversities,including alpha diversity,beta diversity and microbial community composition turnover,in response to precipitation manipulations.A framework is proposed to understand the stability properties of bacteria and fungi under precipitation alteration.We conceived a diagrammatic valley to illustrate microbial stability with the depth representing resistance and the width ecological resilience.Important Findings We found that±60%in precipitation significantly reduced the richness and increased the evenness of bacteria but had trivial impacts on fungi.Precipitation alteration yielded stronger impacts on the variation in alpha diversity of bacteria than fungi,suggesting that the bacterial community is more sensitive to water stress than the fungal community.Moreover,fungi had wider composition turnover than that of bacteria,indicating higher composition variation of fungi than bacteria.The population turnover of fungi,reflected by composition variation,coefficient variation of diversity index and composition turnover,was larger than that of bacteria at both temporal and spatial scales,indicating the population turnover promotes fungal stability.The higher stability of fungal community in tolerating water stress is analogous to a ball in a wide valley that swing substantially but remain close to its steady state;while the lower stability of bacteria community is analogous to a ball that swings slightly but stay far away from its steady state.Our finding that the fungal community had higher stability than bacterial community in a semi-arid grassland might be applicable to other biomes.
基金support partly by RGC Grant 502412,15300514,G-YL04.ZWu acknowledges the Natural Science Foundation of China(61573217),111 project(B12023)the National High-level personnel of special support program and the Chang Jiang Scholar Program of Chinese Education Ministry.
文摘This paper studies the backward-forward linear-quadratic-Gaussian(LQG)games with major and minor agents(players).The state of major agent follows a linear backward stochastic differential equation(BSDE)and the states of minor agents are governed by linear forward stochastic differential equations(SDEs).The major agent is dominating as its state enters those of minor agents.On the other hand,all minor agents are individually negligible but their state-average affects the cost functional of major agent.The mean-field game in such backward-major and forward-minor setup is formulated to analyze the decentralized strategies.We first derive the consistency condition via an auxiliary mean-field SDEs and a 3×2 mixed backward-forward stochastic differential equation(BFSDE)system.Next,we discuss the wellposedness of such BFSDE system by virtue of the monotonicity method.Consequently,we obtain the decentralized strategies for major and minor agents which are proved to satisfy the-Nash equilibrium property.
基金X.Z.was supported by Youth Program of the National Natural Science Foundation of China(31800381)This study was financially supported by projects from the National Natural Science Foundation of China(32071562)a Strategic Priority Research Programon Soil and Microbes of the Chinese Academy of Sciences(XDB15010401).
文摘Aims Water and nitrogen(N)are two key resources in dryland ecosystems,but they may have complex interactive effects on the community structure and ecosystem functions.How future precipitation(rainfall vs snowfall)change will impact aboveground net primary production(ANPP)is far from clear,especially when combined with increasing N availability.Methods In this study,we investigated changes in community productivity,abundance and aboveground biomass of two dominant plant functional groups(PFGs),i.e.perennial rhizome grasses(PR)and perennial bunchgrasses(PB)under the impacts of increased precipitation(rainfall vs snowfall)combined with N addition in a semiarid temperate steppe.Important Findings Summer rainfall augmentation marginally increased community ANPP,whereas it significantly increased the abundance and aboveground biomass of PR,but not those of PB.Summer rainfall addition increased the fraction of PR biomass(fPR)while decreased that of PB(fPB).Spring snow addition had no effect on aboveground biomass of either compositional PFG although it marginally increased community ANPP.Nitrogen addition significantly increased community ANPP with greater increase in PR under summer rainfall addition,indicating strong interactive effects on community ANPP largely by enhancing PR biomass.We also found a nonlinear increase in the positive effect of nitrogen addition on productivity with the increased precipitation amount.These findings indicate an amplified impact of precipitation increase on grassland productivity under the accelerated atmospheric N deposition in the future.